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311.
Agrobiodiversity can provide natural insurance to risk‐averse farmers by reducing the variance of crop yield, and to society at large by reducing the uncertainty in the provision of public‐good ecosystem services, for example, CO2 storage. We analyze the choice of agrobiodiversity by risk‐averse farmers who have access to financial insurance, and study the implications for agrienvironmental policy design when on‐farm agrobiodiversity generates a positive risk externality. While increasing environmental risk leads private farmers to increase their level of on‐farm agrobiodiversity, the level of agrobiodiversity in the laissez‐faire equilibrium remains inefficiently low. We show how either one of the two agrienvironmental policy instruments can cure this risk‐related market failure: an ex ante Pigouvian subsidy on on‐farm agrobiodiversity and an ex post payment‐by‐result for the actual provision of public environmental benefits. In the absence of regulation, welfare may increase rather than decrease with increasing environmental risk, if the agroecosystem is characterized by a high natural insurance function, low costs, and large external benefits of agrobiodiversity.  相似文献   
312.
草畜平衡管理与草地资源可持续利用   总被引:1,自引:0,他引:1  
结合目前载畜量管理的理论发展和我国国情,指出目前实行的草畜平衡管理并不能抑制超载过牧和控制对草地资源的过度利用,所以建议草畜平衡管理由饲草量和牲畜数量之间平衡的管理改变为以草地生态系统的质量变化为主要依据的生态系统管理。  相似文献   
313.
China is facing huge environmental problems, with its current rapid rate of urbanization and industrialization causing biodiversity loss, ecosystem degradation, and land resources degradation on a major scale. To overcome management conflicts and secure ecosystem services, China has proposed a new ‘ecological redline policy’ (ERP) using ecosystem services as a way to meet its targets. By giving environmental policy redline status, China is demonstrating strong commitment in its efforts to tackle environmental degradation and secure ecosystem services for the future. This is already having impact, as the Chinese Ministry of Environmental Protection and the National Development and Reform Commission are prepared to work together to implement the new environmental policy.  相似文献   
314.
Balancing conservation and development with ecosystem services is a popular topic for the sustainable development of agricultural land today. This study establishes an evaluation framework to explore the heterogeneous preferences of tourists and residents for the ecosystem functions of agricultural land in Kinmen, Taiwan. The results showed that respondents preferred to transform the current farming type into sustainable agriculture, increase species habitats, plan wheat and sorghum landscape areas, and combine ecotourism with local cultural activities. Tourists had a higher marginal willingness to pay for farmland conservation than residents. People who supported the conservation program of agricultural land in sorghum and wheat production areas tended to 1) be female, 2) be tourists, 3) have higher education, and 4) have higher monthly income. The results suggest that policymakers must improve ecosystem functions with agricultural ecosystem function support funds, consistent with the guaranteed-price purchase policy in the Kinmen sorghum and wheat areas, for sustainable development.  相似文献   
315.
This research develops the novel concept of an economic ecosystem service sustainability index from the perspective of total income theory, and presents its empirical application at the spatial unit scale of the agroforestry farm. This paper compares the results accrued from applying the refined standard System of National Accounts (rSNA) and the authors’ Agroforestry Accounting System (AAS). The AAS extends the rSNA to capture economic activities without manufactured production costs and substitutes the production cost valuations for exchange values revealed/stated by consumer willingness to pay for consumption of final products without market prices, the aim being to provide more comprehensive figures for total and environmental incomes of the agroforestry farms. Both accounting frameworks are applied to a case study of sixteen large, non-industrial, privately-owned holm oak dehesas (agroforestry farms) in Andalusia-Spain. This dehesa application provides estimates for the economic ecosystem service, total income factorial allocation, total capital and economic ecosystem service sustainability index for the aggregate and individual economic activities of the dehesa, distributed between accounts for the farmer and government institutional sector economic activities. The AAS explicit measurements of the hidden rSNA ecosystem services and environmental incomes of the dehesa allow us to further our scientific understanding of the current and future contributions of environmental income from nature to the total income of society as well as to provide information to the policy makers so that action can be taken to mitigate the depletion and degradation of environmental assets. This dehesa application reveals that environmental income measured by the AAS accounts for 67 % of total income in 2010. The dehesa AAS and rSNA ecosystem services share 34 % and 26 % of total product consumptions, respectively. Coupled with the AAS economic ecosystem service sustainability index of 0.5 and the rSNA economic ecosystem service sustainability index of 0.2, these figures indicate total product over-consumption in 2010. The dehesa case study shows that the AAS ecosystem services and environmental incomes are 2.5 and 8.4 times higher than those of the rSNA, respectively. Once the theoretic robustness of non-market product consumption simulated transaction value is accepted, as in the AAS methodology, the expected official economic ecosystem accounting framework will mainly depend on its ongoing standardization by the United Nations Statistical Division and implementation by individual governments. Thus, the challenge of standardizing and implementing such a framework is more closely linked to governmental policy measures than to the current scientific weakness of non-market product consumption valuations.  相似文献   
316.
For city dwellers urban green space is the primary source of contact with nature. Qualitative green space is increasingly perceived as an important factor for quality of life in urban areas and a key component of sustainable urban design and planning. In this study, the relation between different features of urban green spaces and perception of green space qualities was analyzed by combining the outcome of a survey on green space perception with GIS-based spatial metrics. A survey has been conducted among residents of the Brussels Capital Region and surroundings to assess the relative importance residents assign to different qualities of urban green spaces and how they value these qualities within visited spaces. Quietness, spaciousness, cleanliness and maintenance, facilities and feeling of safety are identified as important qualities of public green spaces, while naturalness, historical and cultural value are perceived as less important qualities. A GIS-based model was developed to infer naturalness, quietness and spaciousness as perceived by users of public green spaces from green space properties. Using variables describing biological value, land-cover composition, green space area and shape, good correlations were obtained between GIS-based assessment of naturalness and spaciousness and how green space users perceive these qualities. The model proposed may be useful for simulating green space development and improvement scenarios and assess their impact on perceived quality. Thus it may serve as a spatial decision support tool for improving the quality of urban green spaces.  相似文献   
317.
The ecosystem services concept is increasingly considered as a policy tool to achieve the sustainable use of natural resources. However, it is still not sufficiently integrated into land use planning. We assessed five land use types (Tetraclinis articulata woodlands, Pinus halepensis plantations, Shrublands, Cereal-almond crops and Cactus groves) in a semiarid area of northern Morocco using empirical data on 17 ecosystem services whose weights were established by 67 stakeholders. The analysis included MCA and direct ranking of the five land uses. Three groups of stakeholders (scientists and managers, collaborators, and direct users of natural resources) were particularly concerned by water supply, protection against erosion and floods, soil fertility and food provision. Multi-criteria analysis showed that the three groups concurred in that Tetraclinis woodlands, crops and cactus fields were the most suitable land uses for the area, regarding ecosystem service provision. Direct ranking confirmed this tendency but showed some divergence between the three groups, as collaborators and users were more inclined towards crops and cactus. The integration of the ecosystem services concept in land use planning is needed to be more practical and easily perceived as a logical response to environmental exigencies and social aspirations.  相似文献   
318.
While appreciation of the fundamental role biodiversity plays in underpinning the long-term sustainability of agricultural systems is growing, international commitments to preserve and protect this natural resource have not yet been achieved. Loss and degradation of farmland habitats are an important contributor to the continued decline of biodiversity. Despite this, little information is available regarding the diversity and ecological condition of farmland habitats in Europe. Indeed, where habitat data are available, this is usually at a very broad landscape scale rather than farm scale. Coupled with this, strategies to increase agricultural output in response to growing global population, will likely place increasing pressure on farmland biodiversity. Knowledge and ongoing monitoring of farmland habitat type and extent is a prerequisite for the future protection of much of Europe’s biodiversity. Here we report the findings of a national scale survey of farmland habitat diversity in Ireland.Detailed surveys of farm habitats and management practices (system, stocking rate agri-environment scheme participation status and organic N and P inputs) were undertaken on 118 farms in three regions of the Republic of Ireland (RoI). Recorded farm habitats were subsequently digitised on orthophotography. The resulting ground truthed data from the total surveyed area of 3688 ha, were then used, together with satellite imagery, to classify the habitat composition of a further approximately 87,000 ha of the surrounding landscape.Results revealed that at individual farm scale, an average of 73% of the land surveyed comprised agriculturally productive (mainly improved grassland) habitats. Marginally productive habitats (mainly extensively managed grasslands) accounted for an average of 11% of farm area, while other semi-natural habitats (mainly hedgerows) accounted for an average of 13%, with the remaining ca. 3% under build ground. Results from the classification at the wider landscape scale showed a similarly substantial incidence of non-intensively managed habitats. However, at both farm and landscape scales, habitat diversity was found to vary markedly between different regions and farming systems.This study represents one of a very small number that currently exist, where farm scale habitat and management data have been collected. From the few that are available, semi-natural habitat cover has been found to account for an average farm area of 1–12%. Therefore, our data present a relatively positive picture in terms of the intensity, scale and impact of Irish farming on landscape heterogeneity. However, as in other parts of the world, agricultural expansion and intensification to meet increased global food supply will necessitate careful monitoring of the impact of these changes on the structure of farmed landscapes. This study provides a novel approach for the collection of such monitoring data at farm scale, and illustrates how such data can be reliably up-scaled to landscape level.  相似文献   
319.
Changing dietary preferences and population growth in South Asia have resulted in increasing demand for wheat and maize, along side high and sustained demand for rice. In the highly productive northwestern Indo-Gangetic Plains of South Asia, farmers utilize groundwater irrigation to assure that at least two of these crops are sequenced on the same field within the same year. Such double cropping has had a significant and positive influence on regional agricultural productivity. But in the risk-prone and food insecure lower Eastern Indo-Gangetic Plains (EIGP), cropping is less intensive. During the dryer winter months, arable land is frequently fallowed or devoted to lower yielding rainfed legumes. Seeing opportunity to boost cereals production, particularly for rice, donors and land use policy makers have consequently reprioritized agricultural development investments in this impoverished region. Tapping groundwater for irrigation and intensified double cropping, however, is unlikely to be economically viable or environmentally sound in the EIGP. Constraints include saline shallow water tables and the prohibitively high installation and energetic extraction costs from deeper freshwater aquifers. The network of largely underutilized rivers and natural canals in the EIGP could conversely be tapped to provide less energetically and economically costly surface water irrigation (SWI). This approach is now championed by the Government of Bangladesh, which has requested USD 500 million from donors to implement land and water use policies to facilitate SWI and double cropping. Precise geospatial assessment of where freshwater flows are most prominent, or where viable fallow or low production intensity cropland is most common, however remains lacking. In response, we used remotely sensed data to identify agricultural land, detect the temporal availability of freshwater in rivers and canals, and assess crop production intensity over a three-year study period in a 33,750 km2 case study area in southwestern Bangladesh. We combined these data with georeferenced and temporally explicitly soil and water salinity information, in addition to relative elevation classifications, in order to examine the extent of winter fallows and low productivity rainfed cropland that could be irrigated by small-scale surface water pumps. Applying observations of irrigated crop sowing dates and yields from 510 wheat, 550 maize, and 553 rice farmers, we also modeled crop intensification production scenarios within the case study area. We conservatively estimate that at least 20,800 and 103,000 ha of fallow and rainfed cropland, respectively, could be brought into intensified double cropping using SWI. Scenario analysis indicates that if 25%–75% of the fallow or low-intensity land were converted to irrigated maize, national aggregate production could increase by 10–14% or 29–42%, respectively. Conversion to wheat would conversely boost national production by 9–10% or 26–31%. Irrigated rice is however unlikely to contribute >3%. In aggregate, these actions could generate between USD 36–108 million of revenue annually among farmers. Intensification therefore has important land use policy and food and income security implications, helping to rationalizei SWI investments. Crop choice, water resource allocation, and water governance will however remain crucial considerations for irrigation planners.  相似文献   
320.
Restoring disturbed and over-exploited ecosystems is an important part of mitigating human pressures on natural ecosystems. An ambitious ecological restoration program, the Grain for Green Program (GFGP), was launched in 1999 in China. We selected the Loess Plateau (LP) as a case study, and evaluated ecosystem changes between 2000 and 2012 using biophysical models, observation records, and literature data. It was observed that both the warming and wetting of climate and the ecological program promoted vegetation growth and biomass production (i.e., carbon sequestration). Overall ecosystem patterns were relatively stable; grassland, residential land, and forest increased in area, while farmland area decreased slightly. Increasing precipitation throughout the study period was related to fluctuations in soil retention and hydrological regulation. Vegetation restoration induced by climate variability and the ecological program played a significant role in soil retention enhancement, which also substantially reduced sediment load. The land-use conversion in ecological restoration program promoted soil carbon sequestration, but featured differences in conversion types and rainfall zones. The ecosystem changes recorded in the LP, which resulted from both the ecological program and climate variability, might be temporary improvements rather than fundamental ecosystem shifts. The success of this ecological restoration in the LP exemplifies the positive effects of environmental policies and the necessity of adopting an adaptive management approach. However, the current assessment was not comprehensive, as it involved only three dominant regulating services, and there were still trade-offs among multiple ecosystem services. Therefore, a deeper understanding of the interactions and trade-offs among ecosystem services is required to explore in the context of emerging climate change, so as to support environmental management that maximizes ecosystem benefits to human well-being.  相似文献   
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